EP0925939A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Printer, image formation method and recording medium
Assignee: Seiko Epson Corp
•
Filing: 1998-04-01
•
Granted: —
•
Expires: 2018-04-01
Abstract
Abstract The present invention prevents deterioration of the quality in interlace printing. The printing system of the present invention uses a head that regulates the amount of ink spouting from nozzles and forms dots of different diameters. While the diameter of dots formed in one primary scan is restricted to a fixed value, the system of the present invention enables dots of different diameters to coexist at an appropriate ratio, thereby improving the printing quality. The printing system of the present invention shifts a nozzle array, in which nozzles are arranged at intervals of a predetermined dot pitch, by a predetermined amount in the secondary scanning direction and varies the dot diameter on every primary scan, while controlling the nozzles in an overlapping state. This enables the dots of different diameters to coexist in a specified area. One preferable application carries out halftone processing under the conditions for dots of a certain diameter at the position where a dot of the certain diameter is formed. This application controls the ratio of dot formation to a desired level. For example, the probability of formation of small-diametral dots is increased in a low-density area. Another preferable application divides the nozzle array on a print head into two groups of nozzles, wherein each group of nozzles forms dots of a specified size. Appropriate selection of the nozzle pitch and the quantity of secondary scanning feed enables printing in which large-diametral dots and small-diametral dots coexist according to a predetermined rule.
Inventors
- 👤 Kazumichi Seiko Epson Corporation SHIMADA
- 👤 Toshiaki Seiko Epson Corporation KAKUTANI
- 👤 Shuji Seiko Epson Corporation YONEKUBO
- 👤 Takahiro Seiko Epson Corporation KATAKURA
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 17:39
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/10; G06K15/102; G06K15/105; H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4057
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
207 words
A printing system for recording at least two types of dots
having different diameters on a printing object and thereby
generating a multi-tone image expressed by recording densities of
said at least two types of dots, said printing system comprising: a head which records a larger-diametral dot out of said at least
two types of dots having different diameters at a first position
that is determined according to a relative position to said printing
object, and records a smaller-diametral dot out of said at least
two types of dots at a second position that is different from the
first position; a position specification unit which determines whether said
head exists at the first position or at the second position, based
on the relative position to said printing object; an input unit which inputs image data including density
information of a target image to be printed; and a multi-valuing unit which carries out a multi-valuing
operation corresponding to a number of tones expressible by said
at least two types of dots based on the input image data, while
changing a condition for formation of a dot according to a type
of the dot to be printed at the position of said head specified
by said position specification unit.
Claim 2
Dependent Claim
142 words
A printing system in accordance with claim 1, said printing
system further comprising: a scanning control unit which causes said head to carry out
a primary scan and a secondary scan relative to said printing object, wherein said head repeats the primary scan and the secondary
scan via said scanning control unit, so as to record a two-dimensional
image, said head having a plurality of dot-forming
elements, which are arranged in a secondary scanning direction and
forms said at least two types of dots, and forming one type of a
dot out of said at least two types of dots on every primary scan,
and wherein said multi-valuing unit carries out the multi-valuing
operation to form a specified type of a dot based on the input image
data on every primary scan in which said head forms one type of
a dot.
Claim 3
Dependent Claim
78 words
A printing system in accordance with claim 2, said printing
system further comprising: a dot formation unit which causes a quantity of feed of said
head in the secondary scanning direction after completion of every
primary scan to be different from a pitch between said plurality
of dot-forming elements, so as to form dots on said printing object
through a plurality of the primary scans at a pitch narrower than
the pitch between said plurality of dot-forming elements.
Claim 4
Dependent Claim
65 words
A printing system in accordance with either one of claims
1 and 2, wherein said multi-valuing unit varies a threshold value,
which is the condition for formation of a dot and used to determine
whether a dot is to be formed or not, according to the type of the
dot to be printed at the position of said head specified by said
position specification unit.
Claim 5
Dependent Claim
36 words
A printing system in accordance with claim 4, wherein said
multi-valuing unit sets a smaller value to the threshold value for
the smaller-diametral dot and a greater value to the threshold value
for the larger-diametral dot.
Claim 6
Dependent Claim
33 words
A printing system in accordance with claim 4, wherein said
multi-valuing unit sets a smaller value to the threshold value for
the smaller-diametral dot when the input image data has a lower
density.
Claim 7
Dependent Claim
40 words
A printing system in accordance with claim 4, wherein said
multi-valuing unit sets a smaller value to the threshold value for
the larger-diametral dot in an area where density of the input image
data is higher than a predetermined level.
Claim 8
Dependent Claim
63 words
A printing system in accordance with either one of claims
1 and 2, wherein said multi-valuing unit varies an evaluation value,
which is the condition for formation of a dot and used to evaluate
a recording density realized by a dot, according to the type of
the dot to be printed at the position of said head specified by
said position specification unit.
Claim 9
Dependent Claim
40 words
A printing system in accordance with claim 8, wherein said
multi-valuing unit carries out binarization and sets a smaller
value to the evaluation value for the larger-diametral dot and a
greater value to the evaluation value for the smaller-diametral
dot.
Claim 10
Dependent Claim
91 words
A printing system in accordance with any one of claims 1
through 9, wherein said multi-valuing unit comprises: an error diffusion unit which diffuses a quantization error
of an image density caused by the multi-valuing operation with
respect to a target pixel to peripheral pixels in the vicinity of
the target pixel; and an image data correction unit which corrects the input image
data with a summation of the quantization errors diffused by said
error diffusion unit, said multi-valuing unit carrying out the multi-valuing
operation based on the corrected image data.
Claim 11
Dependent Claim
54 words
A printing system in accordance with claim 1, wherein said
head reciprocates along a width of said printing object to form
said at least two types of dots, said head forming at least one
type of a dot out of said at least two types of dots only during
a shift in one direction.
Claim 12
Dependent Claim
49 words
A printing system in accordance with either one of claims
1 and 2, wherein said head comprises a mechanism for discharging
ink particles under a pressure applied to each ink running through
an ink conduit by application of a voltage to a piezoelectric element
arranged in said ink conduit.
Claim 13
Dependent Claim
55 words
A printing system in accordance with either one of claims
1 and 2, wherein said head comprises a mechanism for discharging
ink particles under a pressure applied to each ink running through
an ink conduit by air bubbles that are produced by a supply of
electricity to a heating body arranged in said ink conduit.
Claim 14
Independent Claim
194 words
A method of recording at least two types of dots having
different diameters on a printing object by driving a head and
thereby generating a multi-tone image expressed by recording
densities of said at least two types of dots, said head recording
a larger-diametral dot out of said at least two types of dots having
different diameters at a first position that is determined
according to a relative position to said printing object and
recording a smaller-diametral dot out of said at least two types
of dots at a second position that is different from the first
position, said method comprising the steps of: inputting image data including density information of a target
image to be printed; determining whether said head exists at the first position or
at the second position, based on the relative position to said
printing object: and carrying out a multi-valuing operation corresponding to a
number of tones expressible by said at least two types of dots based
on the input image data, while changing a condition for formation
of a dot according to a type of the dot to be printed at the position
of said head thus determined.
Claim 15
Dependent Claim
192 words
A method in accordance with claim 14, wherein said head
repeats a primary scan and a secondary scan relative to said printing
object, so as to record a two-dimensional image, said head having
a plurality of dot-forming elements, which are arranged in a
secondary scanning direction and forms said at least two types of
dots, and forming one type of a dot out of said at least two types
of dots on every primary scan, said method further comprising the steps of: shifting said head in the secondary scanning direction by a
distance that is different from a pitch between said dot-forming
elements on completion of every primary scan; forming dots on said printing object through a plurality of
the primary scans at a pitch narrower than the pitch between said
dot-forming elements; and carrying out a multi-valuing operation corresponding to a
number of tones expressible by said at least two types of dots based
on the input image data, while changing the condition for formation
of a dot on every primary scan, in which said head forms one type
of a dot out of said at least two types of dots.
Claim 16
Dependent Claim
178 words
A recording medium mechanically readable by a computer for
controlling a head which records a larger-diametral dot out of said
at least two types of dots having different diameters at a first
position that is determined according to a relative position to
said printing object and records a smaller-diametral dot out of
said at least two types of dots at a second position that is different
from the first position, said recording medium comprising program code means recorded
thereon, said program code means comprising: a first program code which causes a computer to determine
whether said head exists at the first position or at the second
position, based on the relative position to said printing object;
and a second program code which causes the computer to carry out
a multi-valuing operation corresponding to a number of tones
expressible by said at least two types of dots based on input image
data, while changing a condition for formation of a dot according
to a type of the dot to be printed at the position of said head
thus determined.
Claim 17
Dependent Claim
266 words
A printing system for recording at least two types of dots
having different diameters on a printing object and thereby
generating a multi-tone image expressed by recording densities of
said at least two types of dots, said printing system comprising: a head with a nozzle array that includes a plurality of nozzles
to make a plurality of dots simultaneously and form said at least
two types of dots having different diameters in response to an input
signal; a shifting unit which shifts said head along a width of said
printing object: a head feeding unit which feeds said head relative to said
printing object in a direction perpendicular to the width of said
printing object; and a head driving unit which causes said plurality of nozzles to
spout ink corresponding to a diameter of one type of a dot during
one shift of said head by said shifting unit, thereby forming the
one type of a dot on said printing object, wherein a pitch of said plurality of nozzles on said head and
a quantity of feed by said head feeding unit have a predetermined
relationship, so that at least two nozzles exist to form dots in
a specified area and causes the specified area to be filled with
dots through a plurality of shifts of said head, said printing system further comprising: a control unit which regulates a diameter of dots formed by
said plurality of nozzles on every shift of said head and repeats
the shift of said head by said shifting unit and the feed of said
head by said head feeding unit.
Claim 18
Dependent Claim
25 words
A printing system in accordance with claim 17, wherein said
at least two types of dots coexist at a predetermined ratio in the
specified area.
Claim 19
Dependent Claim
25 words
A printing system in accordance with claim 17, wherein dots
formed in the specified area have an identical diameter along every
shift of said head.
Claim 20
Dependent Claim
25 words
A printing system in accordance with claim 17, wherein dots
formed in the specified area have an identical diameter along every
feed of said head.
Claim 21
Dependent Claim
22 words
A printing system in accordance with claim 17, wherein dots
of different diameters formed in the specified area are arranged
in zigzag.
Claim 22
Dependent Claim
66 words
A printing system in accordance with claim 2, wherein said
head comprises a dot-formation array in which a given number of
dot-forming elements for forming dots are arranged at an interval
of a predetermined pitch in the secondary scanning direction
perpendicular to a primary scanning direction, said dot-forming
elements included in said dot-formation array being driven
simultaneously at a predetermined position in the primary scanning
direction.
Claim 23
Dependent Claim
102 words
A printing system in accordance with claim 22, wherein said
dot-forming elements included in said dot-formation array are
nozzles for spouting ink particles, and wherein said given number of dot-forming elements included in
said dot-formation array are divided into two groups of dot-forming
elements, each group comprising N nozzles, where N denotes an
integer of not less than 2, which are arranged in the secondary
scanning direction at a nozzle interval of k dots, where k denotes
an integer of not less than 2, the two groups of dot-forming elements
being apart from each other by the nozzle interval of k dots.
Claim 24
Dependent Claim
95 words
A printing system in accordance with claim 23, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to repeat a step of repeating a first
path k times and subsequently repeating a second path k times,
wherein said first path carries out the secondary scan after
printing a first-sized dot out of said at least two types of dots
having different diameters, and said second path carries out the
secondary scan after printing a second-sized dot, which is
different in size from the first-sized dot.
Claim 25
Dependent Claim
104 words
A printing system in accordance with claim 23, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to repeat a step of repeating a first
path k times and subsequently repeating a second path k times when
the nozzle interval k is an even value, wherein said first path
carries out the secondary scan after printing a first-sized dot
out of said at least two types of dots having different diameters,
and said second path carries out the secondary scan after printing
a second-sized dot, which is different in size from the first-sized
dot.
Claim 26
Dependent Claim
93 words
A printing system in accordance with claim 23, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to alternately repeat a first path and
a second path when the nozzle interval k is an odd value, wherein
said first path feeds said printing object after printing a
first-sized dot out of said at least two types of dots having
different diameters, and said second path feeds said printing
object after printing a second-sized dot, which is different in
size from the first-sized dot.
Claim 27
Dependent Claim
43 words
A printing system in accordance with claim 24, wherein when
a number of nozzles n are used for printing among N nozzles included
in said head, where n is a positive integer of not greater than
N, k and n are relatively prime.
Claim 28
Dependent Claim
21 words
A printing system in accordance with claim 27, wherein said
secondary scanning control unit feeds said printing object by n
dots.
Claim 29
Dependent Claim
18 words
A printing system in accordance with claim 24, wherein said
first-sized dot is smaller than said second-sized dot.
Claim 30
Dependent Claim
106 words
A printing system in accordance with claim 22, wherein said
dot-forming elements included in said dot-formation array are
nozzles for spouting ink particles, and wherein said given number of dot-forming elements included in
said dot-formation array are divided into an even nozzle group and
an odd nozzle group, each group comprising N nozzles, where N denotes
a positive integer, which are arranged in the secondary scanning
direction at a nozzle interval of 2k dot pitch, where k denotes
a positive integer, each nozzle in the even nozzle group and an
adjoining nozzle in the odd nozzle group being arranged at a fixed
interval of k dots.
Claim 31
Dependent Claim
93 words
A printing system in accordance with claim 30, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to repeat a step of repeating a first
path k times and subsequently repeating a second path k times,
wherein said first path feeds said printing object after printing
a first-sized dot out of said at least two types of dots having
different diameters, and said second path feeds said printing
object after printing a second-sized dot, which is different in
size from the first-sized dot.
Claim 32
Dependent Claim
102 words
A printing system in accordance with claim 30, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to repeat a step of repeating a first
path k times and subsequently repeating a second path k times when
the nozzle interval k is an even value, wherein said first path
feeds said printing object after printing a first-sized dot out
of said at least two types of dots having different diameters, and
said second path feeds said printing object after printing a
second-sized dot, which is different in size from the first-sized
dot.
Claim 33
Dependent Claim
93 words
A printing system in accordance with claim 30, said printing
system further comprising: a secondary scanning control unit which drives said head and
said scanning control unit to alternately repeat a first path and
a second path when the nozzle interval k is an odd value, wherein
said first path feeds said printing object after printing a
first-sized dot out of said at least two types of dots having
different diameters, and said second path feeds said printing
object after printing a second-sized dot, which is different in
size from the first-sized dot.
Claim 34
Dependent Claim
43 words
A printing system in accordance with claim 31, wherein when
a number of nozzles n are used for printing among N nozzles included
in said head, where n is a positive integer of not greater than
N, 2k and n are relatively prime.
Claim 35
Dependent Claim
21 words
A printing system in accordance with claim 34, wherein said
secondary scanning control unit feeds said printing object by n
dots.
Claim 36
Dependent Claim
18 words
A printing system in accordance with claim 31, wherein said
first-sized dot is smaller than said second-sized dot.
References Cited (Backward Citations)
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